Mix the buttermilk with the flour in a saucepan and heat slowly while stirring. Add the raisins and season with a pinch of salt, cinnamon and the zest, as well as the juice of the lemon. Simmer the soup thickly while stirring.
Toast the almonds without fat in a pan until light brown. Whip the cream until stiff.
In a bowl, beat the egg yolks with sugar until frothy. Remove a cup of soup and stir with the egg cream, then stir this into the soup. Take off the stove.
Spread the buttermilk soup on 4 deep plates, pour 1 tablespoon of cream on each and serve sprinkled with the almonds.